Structural and Optical Properties of Tin Doped Zinc Oxide Fibres Prepared By Electrospinning Technique

Abstract

The study synthesized ZnO fibers using electrospinning technique. It also characterized and determined the effects of Sn²⁺ dopant on the optical properties of the fibers synthesized. This was with a view to exploring the potential of improving the performance ZnO semiconductor material in industrial applications.

Polyvinyl Alcohol (PVA) solution was prepared and mixed with ZnO source. Zinc acetate was used as the ZnO source while Tin Acetate was used as Sn²⁺ dopant source. Viscous electrospinning solutions of PVA/Zinc Acetate and three different compositions of Tin Acetate were prepared. The compositions of dopants used were 5, 7 and 9-wt. %. Samples of the depositions from the electrospinning process were annealed at 600^o C at a rate of 4^o C per minute for 6 hours. Scanning electron microscopy (SEM) was employed to reveal the morphology of the depositions. The structural analysis of the fibers was carried out using x-ray diffractometry (XRD) while the optical properties of the fibers were investigated using ultra violet visible spectrophotometry.

The SEM results showed the depositions to be web of fibers. The XRD confirmed the crystallization of undoped and doped ZnO fibers from the acetates. The crystal sizes of the fibers were in the range of 5.566 to 7.202 nm. Furthermore, wide bandgap energy values ranging from 3.26 to 3.46 eV were obtained from the results of the optical properties of the fibers. The results showed that the average crystal sizes of Sn²⁺ doped ZnO fibers were larger than those of the undoped fibers. However, it was observed that the average crystal size decreases with increase in Sn²⁺ content. The results also showed that the bandgap energy values of the fibers increase with dopant concentration.

The study established the viability of fabricating doped and undoped ZnO structure in form of fibers in order to enhance its performance in industrial applications. Also, the results showed that the optical properties of the fibers improved with increase in Sn²⁺ dopant concentration.

Keywords: ZnO fibers; Electrospinning technique; Structural analysis; Optical properties;  Sn²⁺ Dopant; Band gap energy value; Crystal size